From what I recall offhand ( keep in mind this is from both notes and novelizations, so dubious canonicity abounds):

-Jedi Knights have been guardians for 1000 generations.

-Obi Wan and Anakin fought the Clone Wars which happened when they were younger. Skywalker followed Ben on an idealistic crusade which may or may not have been the wars.

-The Republic rotted from the inside due to greed and those power hungry.

-Palpatine gained power at some point thanks to ambitious politicians and powerful commercial entities, but was not necessarily at the same time of the Clone Wars.

-Palpatine seduced Anakin to the dark side.

-Boba Fett is dressed in the armor of a group of warriors who fought the Jedi, in the Clone Wars, supposedly the Mandalorians.

-Skywalker became Vader and fell into a lava pit (and possibly a nuclear reactor) in a battle with Kenobi, thus scarring him.

-Anakin did not know that his wife was pregnant when he turned. Mother Skywalker went with Leia where she was raised by Bail Organa (royalty apparently) and his wife who was the minister of education. Her real mother died when she was 2-3.

-Luke and Leia were separated to keep them safe from Vader and Palpatine.

-Owen Lars was Obi-Wan's brother. (This sticks out most in comparison to A New Hope which implies otherwise).